


an unkindness

by Anonymous



Category: Undertale (Video Game)
Genre: Angst, F/M, Hate Sex, Reader Is Not Frisk (Undertale), Underage Sex Mention, forgiveness isn't everything
Language: English
Status: Completed
Published: 2019-01-22
Updated: 2019-01-28
Packaged: 2019-10-14 10:24:28
Rating: Explicit
Warnings: Major Character Death, Underage
Chapters: 2
Words: 2,840
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17506805
Author URL: https://archiveofourown.org/
Summary: sometimes you can't forgive





	1. Chapter 1

"I fucking hate you" you spit at Sans as he thrusts full hilt inside you in one rough thrust. You both have your clothes on, your skirt flipped up and panties pulled to the side, he had his pants pulled down enough to release his erection and thrust it inside you pinning you to a wall.

"could say the same to you s-sweetheart" he stutters as he begins to pump inside you, wet slapping noises coming from between you as you hiss and scrape your nails on his vertebra. You bite his clavicle and he yelps and groans taking your abuse. You almost want to kill him, you almost want your teeth to break the bone. You almost want to break him and watch him crumble. 

"How fucking long huh? how long was I dating a kid fucker?" you snarl as you hips meet his. 

"heh, heh, years before you sweetheart" his smile gets sharp and deadly "frisk and i have something special, something you and i will never have" he hits the spot inside you that he knows you love roughly and you let out a low moan. "f-fuckin' slut" he moans increasing his speed.

"You're sick, she just went to college you sick fuck. I hate you, I wish I had never met you. Why did you even bother d-dating me?" you're almost close to tears thinking about how he deceived you for so long, how he probably fucked up Frisk, she didn't deserve that, you thought she was a good kid, sad but sweet. Now you know why she was so sad. 

"Was I just a fucking cover for you? To look normal? Fucking asshole" you moan as you feel his magic around you, touching your sensitive spots and playing with your clit. You used to love this feeling, it made you feel so connected to him. You used to just get wet thinking about the color blue.

Until you caught him balls deep in Frisk the night before she left for college. He saw you and he just smirked as he came deep inside her. You ran, not wanting to see anymore. You felt like a fool, a blind idiot. Why didn't you see the signs sooner?! Upon reflection a lot of things made sense. Her guilty looks when you saw her. The way he seemed just a bit too close to her. The private jokes they shared that you brushed off as innocent, they had been close since Frisk was the one that had freed them, Frisk herself used to gush how Sans had helped her in the underground and how she had stayed with the brothers. At most it had seemed like a school girl crush, hell you had one on your 6th grade English teacher. Instead, it was something far more insidious than you could have imagined. 

You clench down on him and push him down using your weight against him, he doesn't fight you and you are on top riding him hard and fast. His face scrunches up in pleasure. You had loved that look on his face, you had loved taking care of him, Sans had been easy to spoil, life in the underground had been hard and there was something about him that made you just want to take care of him. You should have known better when he never really reciprocated. You thought maybe it was a residual mistrust of humans, he seemed to not like many except you and of course, Frisk. Once in a while, he would make you feel special in small ways, little intimate dates, cuddling on the couch, giving you a nice hard fuck, and sometimes he would give you small gifts that you took as thoughtful. After all, money wasn't important, right?

"I n-never want to see you again" you pant, you're close, he knows it and you can feel his cock twitch deep inside and you know he is close too. 

"you know you still love me, when you told me that you loved me i knew i had you forever. could see it in your soul," he whispers almost reverently as he thrust his hips up to meet yours only to still and cum deep inside you. You freeze guilty feeling the pleasure of being filled up one last time. That's what this was right? Last time sex. He was right you had loved him so much, he had thoroughly charmed you and you hated him for it. You felt stupid, you felt lower than dirt. You had come to his house to break up with him after crying and feeling like death for two weeks. All his things he had slowly taken over to your apartment was in a box next to the both of you, the items spilled over on to the floor during the heated argument that devolved to sex quickly. He knew all your buttons and it made you feel so weak. 

You pushed yourself up and off his cock, he growled as he watched the cum leak out of you. You straightened out your clothes and smoothed down your hair as he watched you, his smile back to the soft lazy grin that used to make your heart flutter. Your stomach twisted sourly instead. 

"I'm serious, I never want to see you again. Don't call, don't text, don't come by my job anymore and don't come by my apartment. I hate you, I hate what you did to me and that kid. You're proud how even your voice comes out even though your throat feels closed off. 

"fine, frisk loves me and now she's a legal adult, don't need you anymore" he venomously flings the words in your face, pulling his pants up but staying on the floor. You feel sick

"I hope she finds someone in college and never wants anything to do with you again," you say as you leave, you just hear his low chuckle. 

___

You move on with your life, sadly that means cutting your monster friends out. With them comes Sans, because you swear he knows every monster from the underground. It was easier than you thought it would be, you got a job promotion that took you to another state. You tell your friends and you promise to call, email and keep up with them, but you never do. You even get a new phone and phone number so the notifications stop. 

You leave an anonymous letter at Toriels door the night before you leave. She should at least know. even if she doesn't believe which wouldn't surprise you in the least. Everyone loves Sans and Toriel is his best friend but she still has to know. 

You find new friends, you even find a new boyfriend. He's everything you want and need to get rid of the residual feelings you had for Sans. The sex isn't magical as he was human, but he made sure you at least came twice. 

He gives you thoughtful and lovely gifts, he's patient, kind and understanding. You take care of each other and for once you feel like you aren't the only one in the relationship. He isn't perfect but you both learn from one another. He proposes in a large and elaborate way, at your favorite park at sunset, he had fireworks set off as you shakily told him yes. You marry him after 2 years.

You move on.

He doesn't. 

You find out the day you see an online article announcing the upcoming nuptials of the monster ambassador. Its Frisk grinning the biggest smile you have ever seen her have and next to her isn't the smiley trashbag but a tall, graceful, gorgeous looking human. Frisk's fiance is a dancer lithe and strong. They were going to be married in two days. The accompanying pictures has every monster you met while dating Sans but he isn't in any of the pictures. The satisfaction is as dark as you had thought it would be. For a moment you fully indulge in the feeling, it's like eating dark chocolate, almost too bitter before a small sweetness leaks out. 

You close your eyes and take a breath, and slowly you let go of the feeling and close out the news tab. It's not your problem and you are getting closer to feeling indifferent each day. One day you hope that you can think of Sans as this spot in your life where you were young and too dumb to pick up on obvious tells. It almost feels close and now with that article, it feels even closer. You hope Frisk has a great wedding. 

You're planning out to the grocery store, your husband is at work and you wanted to pick up a few things for dinner and you see Sans as soon as you open your front door. He looks like he had been standing there debating on whether or not he was going to knock. He takes your visage in.

"y-you look good," he mutters 

"You look like shit," you say blatantly. He does, he looks more disheveled than usual, his eyelights look dim not the glowing soft white they used to be. He gives you a sad smile. You don't return it and he looks away, uncomfortable.

You sigh "What do you want Sans?" you just want to get this over with, you hate how you almost pity him. 

"i, i just wanted to see how you were doin' i'm glad you look happy." He looks like this isn't going how he planned. Good. 

"Yeah, I'm happy. Saw the announcement about Frisk, guess that didn't pan out huh?" you can't help it, you dig the knife deeper. Fuck him. You're glad Frisk isn't with him, with all the shit he did to the both of you. You hope her new relationship is healthy and happy, she needs it. 

"yeah, you can say that. look I'm sorry, im really so fucking sorry, i lov-" He tries to say something but you cut him off.

"Look I don't have the time to make you feel better. We all made our choices, yours were just shitty gross ones. I don't blame her, I blame you. You were the adult you sick piece of shit. Now leave before I call the cops." You become ice, sharp and immobile. His eyes get dimmer and he is about to say something else but you back out your doorway and close the door shut, locking it. Groceries can wait. He pounds the door pleading, he just wants to explain himself, he wants to apologize, he still loves you, just please open the door. He was weak, he's so sorry. You lean against the door a few tears running down your face as you hear his first sob. You don't know who you are crying for. 

Soon the crying stops, you hear his fingers scrape the door and then its quiet. You give it 10 minutes before you open the door and he's gone. 

6 months later you get a package with no address. You open it and it holds a small jar nestled in plush packaging along with a letter. Its written in a regal hand explaining who was in the jar, nothing more than a pile of dust and how he thought of you as one of his big favorites.

You take the small jar. It's simple bronze. Open it and see the sparkling dust, it almost looks blue. You pour it down the toilet and flush.

You don't even cry.


	2. Chapter 2

**Notes for the Chapter:**

> So a chapter 2 was asked with the reader waking up...

You wake up, you must have had some kind of terrible night terror as your pillow is soaked with sweat and your eyes feel like you have been crying. You wipe your face with your sheet and get out of bed. It's hellishly early, and you have nothing planned till tonight, but you don't want to go back to sleep.

You can't quite remember what you dreamed about but your heart feels heavy and you don't want to risk getting stuck in a terrible dream. Breakfast sounded better than a nightmare loop.

You eat and tidy your house. It's around noon when you finish and decide that you need to just go out. The heavy feeling hasn't left, not even your favorite songs can lift your mood. Maybe getting lunch at that new monster bar would be novelty enough to knock you out of your funk. Its been 2 years since the barrier on Mt Ebbot was broken and monsters emerged. With the help of a child named Frisk basically stating that monsters weren't going to hurt people and slow integration there is a tentative peace between humans and monsters.

The bar, Grillby's, just opened last week and you had been curious what monster food tasted like. Rumor was that you could eat a ton of monster food and not gain weight but feel full. It didn't take you long to get to the bar, it was maybe a block away and you walked. Instead of the feelings lifting you both anxious and that you were doing the right thing. As you get closer your heart was practically hammering in your throat, you almost turn around and run away from the establishment but instead, like you were on autopilot, you open the door.

Crossing the threshold a wave of nostalgia crashes into you. It doesn't make sense, you have never been here before but the deeper you walk into the bar the déjà vu feeling grows.

All the tables are full so you walk up to the bar, there a few seats left and you take one. A menu is placed in front of you by a tall monster made of flame. You order a draft beer and a burger. He just nods at you, pours your drink in a glass stein and hands it to you before he disappears to the back to place your order.

You hear the door open and a chorus of greetings erupts from the bar.

"Sansy!"

"Sans, how's it goin'? I see you brought the ambassador!"

"Heya Frisk! Glad to see you takin' it easy! You're too busy!"

"had to bribe the kid to take a break, she can't resist grillby's"

You freeze, you want to turn around and look but you can't move, you don't want to move if you move and see who this Sans is you know something terrible would happen. You should leave but you can't move.

  
A skeleton monster in casual clothes sits next to you and next to him is the child ambassador you had seen online and on tv news reports.

You swear you hear a snapping noise and it's like your brain has unlocked. Memories come hard and fast. You strain to keep it together and not scream, you can't scream, you don't want to make a scene as you are flooded moments you haven't lived yet but you did live them.

You were with Sans trading jokes. He laughs and its the best thing you heard. You knew you were in love with him then. He takes you out to Grillby's and when he walks you up to your door he kisses you. You love him. You take care of him and every one of his friends are your friends now. You help Frisk with homework as he stares fondly at you. He was looking at you, right? He starts spending nights at your place, you feel blissfully domestic when he stays over. Its so easy and uncomplicated being with Sans. You are going to ask him to move in with you after you get back home from Frisk's graduation party.

You hear a moan, you hear a moan and you open the door why did you open fucking the door?! They are they fucking and you know it's not the first time as he grins at you and thrusts roughly one last time into Frisk before pulling out and you see his cum leaking out of her. She doesn't even look at you and you are running out.

You hoped it was some fucked up birthday gift, hey you're 18 here's a dick, but he just confirms the worst as he fucks you with abandon. It's last time you fuck him and you feel the bile in your throat. You run away, a coward but you move on. He doesn't and who is touching you? You feel a hard hand on your shoulder, giving you a slight shake.

"hey bud are you o-" he doesn't finish the question as you collide the glass stein, half full with beer into his face, your killing intent dusts him instantly.

You hear screaming, you think its the child that was next to him but they are just staring at you with wide frightened eyes, tears welling up in them.

You're the one screaming.

\----------

 

You wake up, you must have had some kind of terrible night terror as your pillow is soaked with sweat and your eyes feel like you have been crying...

**Notes for the Chapter:**

> Thought of a better ending tweak


End file.
